1. Field of the Invention
The present invention relates to a two-cylinder type rotary compressor used mainly for a refrigerating apparatus or an air conditioning apparatus. More particularly, it relates to a two-cylinder type rotary compressor for reducing pressure loss in a cooling medium intake system.
2. Discussion of the Background
FIGS. 7 and 8 show a conventional two-cylinder type rotary compressor disclosed in Japanese Unexamined Utility Model Publication No. 50793/1981. In FIGS. 7 and 8, a reference numeral 1 designates a driving shaft having eccentric portions 1a, 1b, numerals 2a, 2b respectively designate cylinders each provided with compression chamber 3a or 3b, numerals 4a, 4b designate rolling pistons driven by the eccentric portions 1a, 1b, numerals 5a, 5b designate vanes which are usually in contact with the outer circumferential surface of the rolling pistons, numerals 6a, 6b designate springs for pushing the vanes 5a, 5b, numerals 7, 8 designate bearing plates which cooperate with the cylinders 2a, 2b to form a compression chamber at the inner side of each of the cylinders 2a, 2b, a numeral 9 designates an intermediate partition plate disposed between the cylinders 2a, 2b and separates the compression chambers 3a, 3b at both sides of the plate, a numeral 10 designates a hermetic casing for receiving the two compression elements A, B constructed as above-mentioned, and a numeral 13 designates an intake pipe for a low pressure refrigerant gas which has at one end branched portions which are connected to intake conduits 14, 15 formed in the intermediate partition plate 9.
The operation of the conventional rotary compressor having the construction as above-mentioned will be described.
On actuation of the driving shaft 1, rolling pistons 4a, 4b undergo rolling movement along the inner circumferential surface of the cylinders 2a, 2b. A low pressure refrigerant gas is sucked in a low pressure sections of the compression chambers 3a, 3b through the intake pipe 13 and the intake conduits 14, 15 as indicated by arrow marks in FIG. 8. The low pressure refrigerant gas is compressed in the compression chambers 3a, 3b to become a high temperature and high pressure refrigerant gas and is discharged through a discharge pipe.
In the conventional rotary compressor, complicated machining operations are required since the intake conduits for the refrigerant gas have to be formed in the intermediate partition plate 9. Further, there arises a problem of pressure loss in the intake conduits in the case that a rotary compressor having a large capacity is to be manufactured. To eliminate such disadvantage, it is necessary to form a thick intermediate partition plate so that the inner diameter of the intake conduits is made large. However, this expedient increases a distance between the bearing plates 7 and 8 of the driving shaft, whereby partial abrasion takes place in the bearing plates due to deflection of the driving shaft, this inviting reduction in reliability of the bearing plates and the driving shaft.